Firefly

Lampyridae is a family of insects in the beetle order Coleoptera. 

They are winged beetles, and commonly called fireflies or lightning bugs for their conspicuouscrepuscular use of bioluminescence to attract mates or prey. 

These small animals were discussed not merely by the scientist but frequently appeared in literature, prose and poetry, and also played a prominent part in folklore and medicinal remedies.

There are about 2,000 firefly species. These insects live in a variety of warm environments, as well as in more temperate regions, and are a familiar sight on summer evenings. 

Fireflies love moisture and often live in humid regions of Asia and the Americas. In drier areas, they are found around wet or damp areas that retain moisture.

Fireflies produce a "cold light", with no infrared or ultraviolet frequencies. This chemically produced light from the lower abdomen may be yellow, green, or pale red, with wavelengths from 510 to 670 nanometers.

Fireflies have dedicated light organs that are located under their abdomens. The insects take in oxygen and, inside special cells, combine it with a substance called luciferin to produce light with almost no heat.  To make light, the luciferin combines with oxygen to form an inactive molecule called oxyluciferin.

Firefly light is usually intermittent, and flashes in patterns that are unique to each species. Each blinking pattern is an optical signal that helps fireflies find potential mates. Scientists are not sure how the insects regulate this process to turn their lights on and off.

Firefly light may also serve as a defense mechanism that flashes a clear warning of the insect's unappetizing taste. The fact that even larvae are luminescent lends support to this theory.

Some areas once had so many fireflies that they profited from running firefly tours in marshes and forests—but since human traffic has increased, firefly populations have gone down. Logging, pollution and increased use of pesticides may also contribute to destroying firefly habitat and natural prey.

Fireflies are medically and scientifically useful.

The two chemicals found in a firefly's tail, luciferase and luciferin, light up in the presence of ATP. Every animal has ATP in its cells in amounts that are more or less constant—or should be. In diseased cells, the amount of ATP may be abnormal. If the chemicals from fireflies are injected into diseased cells, they can detect changes in cells that can be used to study many diseases, from cancer to muscular dystrophy.

But that's not all they're used for. Electronic detectors built with these chemicals have been fitted into spacecraft to detect life in outer space, as well as food spoilage and bacterial contamination on earth.

Font: http://en.wikipedia.org/ ; http://animals.nationalgeographic.com/ ; internet

BRAIN

The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. The brain is the most complex organ in a vertebrate's body. 

It is located in the head, usually close to the primary sensory organs for such senses as vision, hearing, balance, taste and smell. 

In a typical human the cerebral cortex (the largest part) is estimated to contain 15–33 billion neurons, each connected by synapses to several thousand other neurons. These neurons communicate with one another by means of long protoplasmic fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specific recipient cells.

Physiologically, the function of the brain is to exert centralized control over the other organs of the body. 

The brain acts on the rest of the body both by generating patterns of muscle activity and by driving the secretion of chemicals called hormones. This centralized control allows rapid and coordinated responses to changes in the environment. Some basic types of responsiveness such as reflexes can be mediated by the spinal cord or peripheral ganglia, but sophisticated purposeful control of behavior based on complex sensory input requires the information-integrating capabilities of a centralized brain.

From a philosophical point of view, what makes the brain special in comparison to other organs is that it forms the physical structure associated with the mind. As Hippocrates put it: "Men ought to know that from nothing else but the brain come joys, delights, laughter and sports, and sorrows, griefs, despondency, and lamentations."

Understanding the relationship between the brain and the mind is a great challenge. It is very difficult to imagine how mental entities such as thoughts and emotions could be implemented by physical entities such as neurons and synapses, or by any other type of mechanism. 

The difficulty was expressed by Gottfried Leibniz in an analogy known as Leibniz's Mill:

One is obliged to admit that perception and what depends upon it is inexplicable on mechanical principles, that is, by figures and motions. In imagining that there is a machine whose construction would enable it to think, to sense, and to have perception, one could conceive it enlarged while retaining the same proportions, so that one could enter into it, just like into a windmill. Supposing this, one should, when visiting within it, find only parts pushing one another, and never anything by which to explain a perception.

— Leibniz, Monadology

The most promising approaches treat the brain as a biological computer, very different in mechanism from an electronic computer, but similar in the sense that it acquires information from the surrounding world, stores it, and processes it in a variety of ways, analogous to the central preocessing unit (CPU) in a computer.

Font: http://en.wikipedia.org

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